I talked to a couple of guys with radicals at different times and both complained that the cars are too fast to have fun during most lapping days. The complaint was essentially that unless a group has free passing or has very few cars, it may be impossible to get a single uninterrupted 10/10th lap during a whole day. Not sure how big of an issue it is, but probably something to consider. But the whole idea is very appealing - fast car that's cheap enough to run and has a racer-grade safety...